The reason it costs more is because it is polymer-modified. It bonds much better to the concrete, sets rapidly, cure fast, it can be feather finished if necessary, and most importantly, it has much more impact resistance for a thin layer.

It is an ideal alternative to regular concrete because it is easy to use and fixes uneven floors in just 4-24 hours. Ideal for DIY projects, self-leveling concrete should only be used when there is no structural damage to the existing concrete floor. It is suitable for use on wood, tiles, and concrete.

Instead of “concrete,” you might see products called “self-leveling underlayment.” This name means the same thing as “self-leveling concrete.” They're generally mixtures of Portland cement, polymer plasticizers, and other ingredients. They have the strength of concrete but flow more easily and are set up quickly.